Obesity among low-income preschool children seems to be on the wane in many areas of the U.S., according to the CDC.

Obesity among low-income preschool children seems to be on the wane in many parts of the U.S., according to the CDC.

From 2008 to 2011, small but significant declines in obesity rates were seen among this group of preschoolers in 19 of 43 states and territories surveyed, Ashleigh May, PhD, of the CDC in Atlanta, and colleagues reported in a Vital Signs report in Morbidity & Mortality Weekly Report.

"Across the 19 states/territories with significant downward trends, the absolute decrease in obesity prevalence from 2008 to 2011 ranged from 0.3 to 2.6 percentage points," the authors wrote. "The relative decreases in obesity prevalence among the 19 states/territories ranged from 1.8% to 19.1%."

However, obesity prevalence is still high in this group, with one in eight low-income preschoolers being obese, the researchers found.

The data offers "a bright spot for our nation's young kids, but the fight is very far from over," Thomas Frieden, MD, MPH, director of the CDC, said during a telephone briefing with reporters.

For their study, May and colleagues assessed height and weight data from 11.6 million low-income children ages 2 to 4 from 40 states, the District of Columbia, and two U.S. territories that participated in the Pediatric Nutrition Surveillance System (PedNSS) from 2008 to 2011.

Over that time, the researchers saw statistically significant downward trends in obesity prevalence in 18 states and the U.S. Virgin Islands.

The Virgin Islands had the greatest decline (adjusted odds ratio 0.92, 95% CI 0.87-0.97), falling from a prevalence of 13.6% in 2008 to 11% in 2011 for an absolute decrease of 2.6 percentage points, the researchers reported.

Florida, Georgia, Missouri, New Jersey, and South Dakota also had some of the largest absolute decreases in obesity prevalence, with declines of more than 1 percentage point in each state, the researchers said.

But 20 states and Puerto Rico had no significant changes in obesity rates, and prevalence rose slightly in three states, May and colleagues noted.

In a secondary analysis that included household incomes for 34 states with complete income data, Montana went from no significant trend to a significant decrease in the prevalence of obesity (aOR 0.97, CI 0.94-1.00).

The study had some limitations. PedNSS only includes low-income children who participated in federal nutrition programs. Also, the findings may not reflect the obesity prevalence and trends of preschool-age children of higher socioeconomic status.

During the briefing, Frieden also noted that obesity prevalence among low-income preschoolers is higher among certain racial and ethnic groups, at a rate of one in five for blacks and one in six for Hispanics.

The exact causes of the declines and leveling in obesity trends are unclear, but May and colleagues suggested that it could have something to do with local and state policies that focus on nutrition and physical activity challenges.

A federal push for women to breastfeed could also have driven some of the changes, Frieden said, although he noted that the effects of breastfeeding on childhood obesity are still controversial.

Other initiatives such as First Lady Michelle Obama's "Let's Move" program may have contributed to declines in childhood obesity, Frieden said.

Sam Kass, executive director of the Let's Move program, who was on the call with reporters, said the program has been "a spectacular success" and "marks a real turning point in our efforts to make sure the youngest generation gets to live healthy and productive lives."